The present invention relates to a winding structure of a stator in a rotating electric machine such as a multiphase AC motor, and more particularly to a winding structure of a stator in a rotating electric machine driven by a plurality of inverters and a drive system of the rotating electric machine.
As a conventional machine, there is known a rotating electric machine such as a servomotor, which is driven by using an inverter circuit thereof. In this kind of rotating electric machine, the inverter circuit thereof feeds a current in a predetermined phase relationship to each of three-phase (UVW-phase) stator windings disposed on a motor stator for rotatably driving a rotor. For the purpose of realizing larger output, it has been proposed to provide a rotating electric machine wherein a plurality of inverter circuits are used, wherein a UVW-phase stator winding is arranged for each of the inverter circuits, and wherein each of the UVW-phase stator windings is divided into a plurality of windings, which are disposed on a motor stator (disclosed in Japanese Patent Application No. 2005-86879, for example).
In a technique disclosed in Japanese Patent Application No. 2005-86879, two sets of UVW-phase stator windings are used as windings 1 and 2, each of the windings 1 and 2 is divided into two windings, a total of 48 slots disposed alternately with teeth on a stator are grouped into four ranges at 90° mechanical angle intervals, and the four ranges thus grouped are designated as the first to fourth quadrants in circumferential order. One of the two divided windings of the winding 1 is disposed in the first quadrant, and the other of the two divided windings of the winding 1 is disposed in the third quadrant opposed to the first quadrant. Likewise, one of the two divided windings of the winding 2 is disposed in the second quadrant, and the other of the two divided windings of the winding 2 is disposed in the fourth quadrant opposed to the second quadrant.
In the above-mentioned arrangement, by dividing each of the windings 1 and 2 into two windings and disposing these windings thus divided in different quadrants (angular ranges), it is intended to increase the output of a rotating electric machine; and further, by arranging the windings 1 and 2 so as not to spatially overlap each other, it is also intended to prevent magnetic flux interference between the windings 1 and 2.